System and method for high pressure delivery of gas-supersaturated fluids

ABSTRACT

A system and method for generating a gas-supersaturated fluid and delivering the fluid at high delivery pressures to thereby prevent bubble nucleation is disclosed. The system comprises a housing for containing a removable fluid assembly for housing a fluid to be gas-supersaturated and a drive assembly for delivering the fluid to a delivery site. The housing assembly comprises a cylinder and a piston which-may be advanced along the inner surface of the cylinder to pressurize and to deliver the fluid. To generate a gas-supersaturated fluid, the housing assembly is removed from the system housing, filled with a fluid, and gas is introduced at or slightly above the desired gas partial pressure into the cylinder. To deliver the gas-supersaturated fluid, the fluid assembly is returned to the system housing and the drive assembly advances the piston to increase the hydrostatic pressure to the desired delivery pressure and, after opening a valve, to deliver the gas-supersaturated fluid at the desired high delivery pressure to a delivery site.

CROSS REFERENCE TO RELATED APPLICATIONS

This patent application is a divisional of U.S. patent application Ser.No. 09/882,798, filed on Jun. 14, 2001, now U.S. Pat. Ser. No.6,782,924, which is a divisional of U.S. patent application Ser. No.09/467,673, filed on Dec. 21,1999, now U.S. Pat. Ser. No. 6,315,754,which is a continuation of U.S. patent application Ser. No. 09/200,608,filed on Nov. 30, 1998, now U.S. Pat. Ser. No. 6,030,357, which is acontinuation of U.S. patent application Ser. No. 08/915,531, filed onAug. 15,1997, now U.S. Pat. Ser. No. 5,893,838, all of which areincorporated herein by reference.

FIELD OF THE INVENTION

The present invention generally relates to a system and method for thegeneration and delivery of high pressure gas-supersaturated fluids. Morespecifically, the present invention relates to a system and method forgenerating a gas-supersaturated fluid and delivering the fluid at highpressures without bubble formation.

BACKGROUND OF THE INVENTION

Prior art infusion devices have been developed for drug delivery,angiographic dye injection and precision fluid infusion. In general,such infusion devices only support small delivery volumes (approximately60 cc) at low (for example, less than 20 psi) to medium (for example, upto 1000 psi) delivery pressures.

A system and method capable of delivering a large volume of fluid at anaccurate delivery rate may be desirable, for example, for enrichingblood with an oxygen-supersaturated solution to provide regional orsystemic support to a patient. Another application of oxygensupersaturated fluid would be delivery downstream of a balloonangioplasty site, such as by perfusion guidewire, to reduce or preventlocalized ischemia. For delivery and infusion of gas-supersaturatedfluids, such as an oxygen supersaturated solution, a high deliverypressure (for example, 4,000 psi) may be desirable to prevent bubblenucleation or formation. An example of a system for delivering gassupersaturated fluids without bubble formation is disclosed in U.S. Pat.No. 5,599,296. When fluid is delivered at high pressures, it is alsodesirable to provide a safety mechanism for terminating fluid deliverywhen the delivery pressure exceeds a predetermined limit.

In order to deliver the fluid at a desired volume delivery rate and/orto deliver a desired total volume of the fluid, it is also desirable toprovide accurate control of the delivery rate and thus accurate controlof the total fluid volume delivered.

In spite of recent advances in the art, for example the above-mentionedU.S. Pat. No. 5,599,296, there remains a need in the art for a fluiddelivery system and method for generating and accurately delivering alarge volume of gas-supersaturated fluid. There remains a further needin the art for a system capable of generation and delivery ofgas-supersaturated fluid at high delivery pressures in order to preventor minimize bubble nucleation and formation upon infusion into apatient. There remains yet a further need in the art for a fluiddelivery system and method for providing a safety mechanism to protectpatients and operators by interalia, terminating the fluid delivery ifthe delivery pressure exceeds a predetermined limit. There remains yet afurther need in the art for a fluid delivery system and method foraccurate control of the delivery rate and pressure and thus accuratecontrol of the total fluid volume delivered.

SUMMARY OF THE INVENTION

Preferred embodiments of the present invention meet the foregoing needsby providing a system and method for generating a large volume ofgas-supersaturated fluid and delivering the fluid to a fluid deliverydevice at specified fluid delivery rates and at high delivery pressuresto prevent bubble nucleation.

The fluid delivery system of the present invention comprises a systemhousing for containing a removable fluid housing assembly and a drivemechanism assembly. The removable fluid housing assembly comprises acylindrical fluid housing and a piston which travels along the innersurface of the fluid housing.

The fluid housing assembly is first removed from the system housing andfilled with a fluid. The fluid in the fluid housing assembly issupersaturated by introducing a gas at or slightly above the desired gaspartial pressure of the fluid. The fluid housing assembly is thenreturned to the system housing and the drive mechanism assembly advancesthe piston to increase the hydrostatic pressure of the fluid within thefluid housing until the desired delivery pressure is obtained.

Use of the fluid housing for both generating and delivering thegas-supersaturated fluid simplifies the system configuration byeliminating additional components and also simplifies the method forgenerating and delivering the gas-supersaturated fluid by eliminatingthe step of transporting the fluid from one fluid housing to another.Generating and delivering the gas-supersaturated fluid in a single fluidhousing also greatly minimizes the issues of corrosion of the fluidhousing, contamination of the fluid and bubble nucleation in the fluid.

After the hydrostatic pressure of the fluid within the fluid housingreaches the desired delivery pressure, the gas-supersaturated fluid isdelivered through a fluid output tubing for delivery of the fluid to adesired delivery site. For fluid delivery to a patient, for example, ahollow perfusion guide wire or other appropriate delivery device isconnected to one end of the fluid output tubing. The fluid delivery rateis controlled and can range from 1 ml/hr to greater than 3,000 ml/hr.

The system of the present invention provides a compact system forgeneration and delivery of gas-supersaturated solutions in aconfiguration and size very similar to conventional infusion pumps.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial cross-sectional front-view of a high pressureinfusion system of the present invention;

FIG. 2 is a partial cross-sectional side view of the high pressureinfusion system of FIG. 1;

FIG. 3 is a partial cross-sectional front view of a fluid assembly ofthe high pressure infusion system of FIG. 1;

FIG. 4 is a bottom view of the fluid assembly of FIG. 3;

FIG. 5 is a side view of the fluid assembly of FIG. 3;

FIG. 6 is a partial cross-sectional side view of a portion of a highpressure infusion system with an alternative embodiment of a fluidassembly;

FIG. 7 is a cross-sectional view of an alternate exemplary pistonassembly of the high pressure infusion system of the present invention;

FIG. 8 is a cross-sectional top view of the high pressure infusionsystem of FIG. 1 showing a drive system;

FIG. 9 is a cross-sectional top view of the high pressure infusionsystem of FIG. 1 showing a main bearing and a piston pusher, and apiston pusher anti-rotation plate;

FIG. 10 is a front view of the high pressure infusion system of FIG. 1showing a user interface; and

FIG. 11 is a schematic diagram of a separate support and jack used influid processing according to one embodiment.

DETAILED-DESCRIPTION OF THE INVENTION

The structure and function of the preferred embodiments can be bestunderstood by reference to the drawings. Where the same referencenumerals appear in multiple figures, the numerals refer to the same orcorresponding structure in those figures.

As shown in FIGS. 1 and 2, high pressure fluid delivery system 10 of thepresent invention generally comprises fluid assembly 20 for generatingand holding a fluid to be gas-supersaturated and delivered, and driveassembly 30 for delivering the gas-supersaturated fluid from the fluidassembly at a high delivery pressure. Fluid and drive assemblies 20, 30are mounted in housing 40 with fluid assembly 20 being removable asexplained below.

As best shown in FIGS. 3-5, fluid assembly 20 comprises cylinder 50,piston 52, cylinder output fitting 58, housing output tubing 54 andoutput manifold 56. Housing output tubing 54 connects fitting 58 tomanifold input port 60. Manifold 56 monitors the hydrostatic pressure ofthe fluid in cylinder 50. Cylinder 50 is preferably made of a corrosionresistant and strong material, such as titanium- In order to ensuresmooth travel of piston 52 within cylinder 50, the interior surface ofcylinder 50 is preferably smooth.

Piston 52, as shown in FIGS. 1, 2 and 3, comprises high pressure seal62, guide ring 64, fluid and gas introduction barrier 66 and port 68.High pressure seal 62 prevents undesired escape of gas and/or fluid fromthe cylinder. High pressure seal 62 is preferably U-shaped such thatseal 62 is at least partially forced against the inner surface ofcylinder 50 by the pressure of the gas and/or fluid within cylinder 50.Thus, an increase in the pressure of the gas and/or fluid withincylinder 50 increases the sealing force exerted by seal 62 against theinner surface of cylinder SO and thereby resulting in a stronger seal.

A trocar or other suitable cannula is inserted into port 68 for theintroduction of fluid and gas into . cylinder 50 through introductionbarrier 66. Introduction barrier is preferably a manually operated ballvalve such that a seal is maintained after the cannula is removed from,port 68, especially for hydrostatic pressures approximately 500 psi orhigher. See FIG. 7. Alternatively, for hydrostatic pressuresapproximately 500 psi or less, introduction barrier 66 may be made of amedical grade silicon rubber (not shown in FIG. 7; see FIGS. 1-3) suchthat a seal is maintained when pierced by the cannula during theintroduction of fluid and gas into cylinder 50.

Piston 52 may also provide threaded annular recess 67. Threaded annularrecess 67 allows for attachment of a piston handle (not shown) tofacilitate movement of piston away from fitting 58 and to facilitateremoval of piston 52 from cylinder 50, especially when the contents ofthe cylinder are not pressurized. Removal of piston 52 may desirable,for example, to clean interior surfaces of cylinder 50.

An alternate exemplary piston assembly 55 is shown in FIG. 7. The pistonassembly 55 advantageously comprises a ball valve assembly 170 includinga valve seat assembly 172 in threaded sealed engagement with the piston52 and with the ball valve actuator 174. A fluid pathway extends throughthe ball valve actuator 174 between the fluid inlet port 176 and the endof the fluid pathway proximate the ball 178. When the actuator 174 isrotated to move toward the fluid outlet 180, a portion of the actuator174 presses against and moves the ball 178 downward against the actionof spring 182. In this first position, fluid provided via fluid inletport 176 may be introduced through the piston 52, e.g., to fill thefluid receptacle of a fluid assembly. When the actuator 174 is rotatedto move away from the fluid outlet 180, the actuator loses contact withthe ball 178. In this second position, the ball 178 seats against aportion of the valve seat assembly 172 as a result of the action of thespring 182 and any pressure within the fluid receptacle of the fluidassembly. Thus, for example, any fluid under pressure within thereceptacle cannot escape through the valve assembly 170, however anyfluid supplied to fluid inlet port 176 at a pressure greater than thepressure of the ball 178 against its seat may be introduced into thereceptacle.

In an alternative embodiment, as shown in FIG. 6, fluid assembly 20 alsoincludes disposable and replaceable fluid container 70 within cylinder51. Preferably, cylinder is hinged along a curved surface for ease ofinserting disposable container 70 into and removing disposable container70 out of cylinder 51. Disposable container 70 provides output port 71for attachment to fitting 59 for the delivery of fluid from disposablefluid container 70.

Disposable container 70 may be tubular and made of a flexible andcollapsible material, and when properly supported, capable ofwithstanding pressures of 5,00.0 psi or greater. As shown in FIG. 6,disposable container 70 may also be provided with preset fold lines 73such that when piston 53 advances toward fitting 59 and compressesdisposable container 70, disposable container 70 collapses in apredetermined manner and thereby minimizes risks of rupture. Flexibledisposable fluid container 70 may further provide an input port (notvisible in FIG. 6) for attachment to a port for the introduction offluid and gas into disposable container 70.

Alternatively, disposable container 70 may be made of a rigid plasticsuch that disposable container 70 does not fold or collapse withincylinder 51. One end of rigid disposable container 70 proximate to apiston is open and thereby eliminating the need for, an input port. Theopen piston end of rigid disposable container 70 allows the piston totravel along the inner surface of rigid container.

Although the following description describes system 10 with flexible andcollapsible disposable fluid container 70, one of ordinary skill in theart can easily adapt and apply the following description to system 10with the use of rigid disposable container 70 or without the use ofdisposable fluid container 70.

In order to generate a gas-supersaturated fluid, fluid assembly 20 isremoved from delivery system housing 40. Disposable container 70 isinserted into cylinder 51 such that the input port of container 70 isconnected to a fluid inlet port. To fill disposable container 70 with afluid, for example physiological saline or lactated ringers solution, acannula connected to a fluid source, such as a syringe, is insertedthrough an introduction barrier and the fluid is introduced intodisposable container 70 via the port.

In this exemplary embodiment, the volume of cylinder Si and the maximumvolume of disposable container 70 is approximately 1.1 liters.Preferably, fluid is introduced until disposable container 70 fillscylinder 51 and is completely filled with the fluid. A small knownvolume of fluid, for example 0.1 liter, is removed from disposablecontainer 70 through the cannula resulting in the same known volume ofair above the fluid within disposable container 70. Thus, the volumes offluid and air within disposable container 70 are known. In thisexemplary embodiment, disposable container 70 contains approximately 1.0liter of fluid and 0.1 liter of air.

To gas-supersaturate the fluid in disposable container 70, fluidassembly 20 is inverted such that piston 53 is below fitting 59 and atan end of cylinder 51 opposite fitting 58. A gas source is connected tothe cannula in place of or in combination with the fluid source. Thegas, such as oxygen, is introduced into disposable container 70 via thefluid inlet port at a pressure that is the same or slightly above thedesired resultant partial pressure of the gas.

As gas bubbles flow upward through the fluid in disposable container 70,the gas is dissolved into the fluid and also displaces other previouslydissolved gases in the fluid. Excess undissolved gas exits disposablefluid container 70 and cylinder 51 through fitting 59. Because of therelatively quick diffusion process due to the relatively large surfacearea of the gas bubbles, the process of gas-supersaturating the fluidcan be completed in a short period of time. For example, with a gas flowof 5-10 standard ft³/hr in a 1.1 liter cylinder, the fluid can begas-supersaturated in approximately 1 hour.

After gas-supersaturating the fluid to the desired gas partial pressure,the cannula is removed from the introduction barrier. A piston cap (see,e.g., piston cap 72 of FIGS. 1-2) may be attached onto cylinder 51 overpiston 53. Because the contents of fluid container 70 are underpressure, the piston cap facilitates in retaining piston 53 completelywithin cylinder 51 prior to returning fluid assembly 20 to deliverysystem housing 40. The piston cap may define an annular lip forretaining piston 53 further within cylinder 51.

A support structure 200 (FIG. 11) for holding fluid assembly 20 may beutilized such that piston 53 can be advanced with, for example, jack202. A variety of arrangements other than that shown schematically inFIG. 11 may be devised for this purpose. A valve is opened and piston 53is advanced upward toward fitting 58 just-until fluid begins to exitthrough the valve. Thus, the volume of gas above the fluid withindisposable container 70 has been eliminated. The valve is preferably atwo-way valve, especially for high gas partial pressures. At lower gaspartial pressures (about 15 psi), fitting 59 may be disconnected and aseparate valve assembly may be connected to cylinder 51. After thevolume of gas is removed, additional fluid is then added into disposablecontainer 70, for example, with a high pressure syringe, to increase thehydrostatic pressure above the desired gas partial pressure. As anexample with the system described above, pressure may be increased from500 psi to 750-1000 psi. Alternatively, the high pressure syringe may beused instead of jack 202 to eliminate the gas space in the cylinderwhile maintaining the pressure. The valve is then closed to preventfurther escape of fluid or gas through the valve.

It may be desirable to store the gas-supersaturated fluid in disposablecontainer 70 under an increased hydrostatic pressure in order todissolve or minimize the size of any bubble nuclei in the fluid and inorder to store the fluid for a period of time until the fluid is to bedelivered. To increase the hydrostatic pressure of the fluid withindisposable container 70, piston 53 can be advanced further. For example,piston 53 may be advanced until the hydrostatic pressure is increased asignificant amount over the gas partial pressure. Increasing thehydrostatic pressure also helps to prevent the hydrostatic pressure fromdropping below the gas partial pressure as a result of, for example, adecrease in the temperature of the fluid and therefore also helpsprevent bubble nucleation.

For gas partial pressures of approximately 50 psi or less, because fluidassembly 20 can be removed from the support structure 200 and loadedinto delivery system housing 40 in a relatively short period of time,for immediate delivery of the gas-supersaturated fluid, use of pistoncap 72 may not be necessary. At such gas partial pressures, even withoutthe use of piston cap 72, few bubble nuclei, if any, would form asbubble nuclei require a relatively longer period of time to form and anydecrease in the hydrostatic pressure as a result of not using piston cap72 to retain piston 52 completely within cylinder 51 would be relativelysmall.

After gas-supersaturating the fluid, fluid assembly 20 is removed fromthe support structure 200 and returned to delivery system housing 40.Fluid assembly 20 is oriented within system housing 40 such that piston53 is above fitting 58 and coupled to drive assembly 30 for highpressure delivery of the gas-supersaturated fluid to a desired site.

As shown in FIGS. 1-2 and 8-9, drive assembly 30 generally comprisesdrive system 80-for driving ball screw 82; main bearing 84 and supportbearing 86 for engaging with ball screw 82; piston pusher 88 driven byball screw 82 for advancing piston 52 toward fitting 58; travel limitswitches 90 for ensuring that piston pusher travel is withinpredetermined limits; and piston pusher anti-rotation plate forpreventing ball screw 82 from rotating piston pusher.

Drive system 80 as shown in FIGS. 1 and 8 comprises stepper motor 94 fordriving high torque gear box 96 (with a gear ratio of, for example,112:1) which drives drive gear 98 (with a gear ratio of, for example,4:1). Drive gear 98 in turn drives main gear 100, fixably attached toball screw 82 and ratchet wheel 102 and pawl 104. When pawl 104 engagesratchet wheel 102, pawl 104 prevents main gear 100 and piston pusher 88from rotating in an undesired direction, even if power to system 10 isterminated. Thus, ratchet wheel 102 and pawl 104, when engaged, preventpiston pusher 88 and piston 52 from traveling upward and away fromfitting 58.

As shown in FIGS. 1-2, main and support bearings 84, 86 each engage andsupport an end of ball screw 82 near drive system 80 and near pistonpusher anti-rotation plate 92, respectively. Main bearing 84 and supportbearing 86 help to minimize frictional loading from direct load forcesand from side load forces due to possible imperfect alignment of ballscrew 82 and/or piston 52. Main bearing 84 and support bearing 86 alsoensure concentric rotation of ball screw 82 even under high loads fromthe high pressures within cylinder 50. Having a two bearing arrangementprovides superior alignment and support which allows high pressure fluiddelivery to be achieved and accurately controlled without an oversizedor bulky apparatus.

Piston pusher 88 comprises upper engagement portion 106 and lower splitportion 108. Engagement portion is annular with a threaded interior forcoupling with ball screw 82 such that rotation of ball screw 82 advancespiston pusher 88 either toward or away from fitting 58 depending on thedirection of ball screw rotation. The use of ball screw 82 to advancepiston pusher 88 also provides an accurate measure of the fluid deliveryrate and the total fluid volume delivered.

Engagement portion 106 of piston pusher 88 includes flange 110 whichacts as a travel limit switch activator such that functions of driveassembly 30 are terminated when flange 110 makes contact with either oftwo travel limit switches 90, thereby ensuring that piston pusher travelis within the predetermined limits.

As shown in cross-sectional view in FIG. 9, split portion 108 of pistonpusher 88 comprises two semi-circular sections to allow piston pusher 88to travel past support bearing 86, anti-rotation plate 92 and piston cap72. Piston pusher anti-rotation plate 92 is fixably attached to deliverysystem housing 40 and provides one or more apertures 112, through whichthe two semi-circular sections of split portion 108 may travel. Pistonpusher anti-rotation plate 92 prevents rotation of piston pusher 88 suchthat rotation of ball screw 82 advances piston pusher 88 either towardor away from fitting 58 depending on the direction of ball screwrotation. Piston pusher anti-rotation plate 92 may also support supportbearing 86. Piston cap 72 similarly provides one or more apertures forallowing piston pusher 88 to travel past piston cap 72.

As shown in FIG. 10, to facilitate operation of system 10, a userinterface is provided on front panel 120of delivery system housing 40for allowing a user to specify and control operating parameters andindicating to the user certain operating parameters. The user interfacemay include power switch 114 for supplying and cutting off power tosystem 10; LOAD button 115 for fluid delivery preparation : by advancingpiston pusher 88 until the hydrostatic pressure approximately equals thedesired delivery pressure; a FLOW switch 116 for increasing anddecreasing the fluid delivery rate; a RATCHET switch (not shown) forengaging and disengaging pawl 104 from ratchet wheel 102 to prevent orallow rotation of ball screw 82 in a direction that advances pistonpusher 88 upward and away from fluid assembly 20; UNLOAD button 117 foradvancing piston pusher 88 upward after disengaging pawl 104 fromratchet wheel 102; and an ALARM ACKNOWLEDGE 118 button to allow the userto acknowledge an indicated error and continue fluid delivery.

The user interface may further provide displays 119, 121 to indicate thespecified delivery rate (e.g. 10.5 cc/min) and the total volumedelivered (e.g. 275 cc). The user interface may also provide variouslights 123 to indicate certain operating conditions of system 10.

To prepare system 10 for delivery of the gas-supersaturate fluid influid assembly 20, the user inputs the necessary operating parameterssuch as the fluid delivery rate, total fluid delivery volume, and fluiddelivery pressure. The user then depresses LOAD button 115 on the userinterface. By pressing LOAD button 115, piston pusher 88 advances piston52 toward fitting 58 until the hydrostatic pressure of the fluid withindisposable container 70 reaches the desired delivery pressure. Suchfurther pressurization of the fluid also serves as a final compressionand stabilization of the gas-supersaturated fluid within disposablecontainer 70. The desired delivery pressure is dependent upon thedesired fluid delivery rate and the size of system fluid delivery device122 used for fluid delivery to the desired site. Lights 123 may providean indicator for indicating when the hydrostatic pressure has reachedthe desired delivery pressure.

To monitor the temperature of the fluid in cylinder 50, system 10 mayprovide a pair of thermistors 123 located in the interior cylindricalwall of cylinder 50.

The pair of thermistors provides redundancy in order to ensure reliableand accurate monitoring of the temperature of the fluid. System 10 mayfurther provide a heater jacket (not shown) encircling cylinder 50 tocontrol the temperature of the fluid therein. With a pair of redundantthermistors and a heater jacket to control the temperature, system 10provides accurate and reliable control and monitoring of the temperatureof the fluid in cylinder 50. This may be especially desirable, forexample, when a significant fluid flow, for example 10-50 cc/min, isdelivered to a patient's coronary arteries.

System 10 may further comprise a flow meter to monitor the output flowvelocity of the fluid from cylinder 50. To monitor the hydrostaticpressure of the fluid from cylinder 50, manifold 56 comprises a fluidpressure sensor. In order to prevent fluid delivery at an excessivelyhigh delivery pressure, manifold 56 may further comprise rupture disc124 in fluid communication with the fluid to be delivered. When thefluid delivery pressure exceeds the maximum pressure rupture disc 124withstand, rupture disc 124 ruptures. After rupture disc 124 ruptures,fluid flow to system fluid delivery device 122 for fluid delivery to thedesired site terminates and fluid flow is redirected away from system10.

Fluid flows out of cylinder 50 through housing output tubing 54 and intomanifold 56. As, shown in FIGS. 3 and 5, fluid flows out of manifold 56via two-way flow/flush valve 126 of manifold 56. When open, two-wayflow-flush valve 126 allows delivery of either the gas-supersaturatedfluid or a flush fluid (such as saline) to the desired delivery site ata low fluid delivery rate. Such low delivery of a flush fluid allows acontinuous fluid flow to the fluid delivery site. For example, whensystem 10 is utilized to deliver gas-supersaturated fluids to a patient,even when fluid delivery at the specified delivery rate is no longernecessary or desired, maintaining a continuous fluid flow may bedesirable to prevent coagulation problems.

Output fluid filter 128 may be provided to filter fluid flowing fromtwo-way valve 126. Fluid is then delivered from output fluid filter 128to the delivery site via system fluid delivery device 122. For example,for delivery of the gas-supersaturated fluid to a patient, system fluiddelivery device 122 may be an infusion device comprising a 400 cm flexspiral tubing connected to a guidewire.

The present invention has been described in terms of exemplaryembodiments. The invention, however, is not limited to embodimentsdepicted and described. Rather, the scope of the invention is defined bythe appended claims.

1. A system for delivering fluid to a delivery site comprising: a fluidassembly comprising a receptacle for containing fluid and a pistonadapted to travel within the receptacle, the piston comprising: a sealadapted to seal the piston within the receptacle; a port extendingthrough the piston; and a valve operatively arranged relative to theport to permit introduction of the fluid into the receptacle; a driveassembly positioned adjacent the fluid assembly to advance the pistonwithin the receptacle to pressurize the fluid; and a flow deliveryassembly coupled to the fluid port of the receptacle to deliver thepressurized fluid to the delivery site.
 2. The system, as set forth inclaim 1, wherein the valve comprises a check valve, the check valvehaving a valve seat, a ball, and a spring, the spring biasing the balltoward the valve seat.
 3. The system, as set forth in claim 2, whereinthe piston comprises an actuator being moveable in a first direction tomove the ball away from the valve scat and being moveable in a seconddirection to move the ball into contact with the valve seat.
 4. Thesystem, as set forth in claim 3, wherein the fluid may be introducedinto the receptacle through the piston when the actuator moves the ballin the first direction.
 5. The system, as set forth in claim 2, whereinthe fluid maybe introduced into the receptacle through the piston whenthe fluid overcomes the force of the spring to move the ball away fromthe valve seat.
 6. The system, as set forth in claim 1, wherein the portis adapted to accept a cannula for the introduction of the fluid intothe receptacle.
 7. The system, as set forth in claim 1, wherein thereceptacle comprises a piston cap which retains the piston within thereceptacle.
 8. The system, as set forth in claim 2, wherein the checkvalve prevents the fluid from escaping from the receptacle.
 9. Thesystem, as set forth in claim 1, wherein the seal comprises a highpressure seal disposed about a peripheral portion of the piston.
 10. Thesystem, as set forth in claim 1, wherein the drive assembly comprises adrive screw and a piston pusher, the piston pusher being disposed on thedrive screw and being moveable along the drive screw and into contactwith the piston in response to rotation of the drive screw.
 11. Thesystem, as set forth in claim 10, wherein the drive assembly comprises amotor being drivingly coupled to a gear box, the gear box being operablycoupled to the drive screw to cause rotation of the drive screw.
 12. Thesystem, as set forth in claim 1, comprising a housing, the fluidassembly and the drive assembly being disposed in the housing.
 13. Thesystem, as set forth in claim 1, comprising a display coupled to thesystem to indicate given operating parameters to a user.
 14. The system,as set forth in claim 1, comprising a control panel coupled to thesystem to input given operating parameters into the system.
 15. Thesystem, as set forth in claim 1, wherein the flow delivery assemblycomprises a manifold having a control valve in fluid communication withthe fluid port, the valve being in fluid communication to a fluiddelivery device which delivers the pressurized fluid to the deliverysite.